Download DNa introduction

Chapter 11 DNa introduction
Forensics Uses
• DNA evidence has been used to
investigate crimes, establish paternity,
and identify victims of war and largescale disasters
Science and the Law: the Implications of DNA Profiling
New York State to Exonerate Innocent Prisoners Using DNA
The Smoking Gun, 9/11 DNA Evidence Revisited
DNA Paternity Test – Worldwide Increase
Background information
• Body consists of 60 trillion cells
– Most of these cells contain a nucleus
The exception = Mature red blood cells
– Each nucleus contains the genetic material,
or the directions, to make us who we are
• The genetic material is found in structures called
chromosomes
Background information
• Chromosomes are composed of little
segments called genes
– The gene is the fundamental unit of heredity
Holds instruction for the body cells to make
proteins that determine everything from hair
color to our susceptibility to disease
• Each gene is composed of a specific
sequence of DNA
Dna
• DNA stands for deoxyribonucleic acid
– Blueprint, or directions, for all living things
– Universal – found in every living thing
• In humans, DNA is in the form of a double
helix, or spiral ladder
Shape was discovered by James Watson and
Francis Crick in 1953
Dna components
• DNA is made up of primary units called
nucleotides
– Each nucleotide is composed of three pieces
Sugar (deoxyribose)
Phosphate group
Nitrogenous base
– Four different bases: Adenine, Guanine, Thymine,
Cytosine
DNA shape
• The sugar and the phosphate group
create the backbone of the molecule
– This is the sides of the ladder
• The bases are the rungs of the ladder
Base pairing rule
• Each base matches up with one other specific
base = base pairing rules
Adenine will always bind to thymine, and vice versa
Cytosine will always bind to guanine, and vice versa
• Each DNA strand contains over 1 million base
pairs
– It is the order of bases that dictate your traits
Types of Dna
• Nuclear
• Mitochondrial
• Found in the nucleus
• Constitutes 23 pairs of
chromosomes inherited
from both parents
• Each cell contains only
one nuclei
• Found in the cytoplasm
• Is inherited only from
mother
• Each cell contains
hundreds of thousands
of mitochondria
• Can be found in skeletal
remains
Nuclear DNA is present in the head of the sperm. Mitochondrial DNA is present in the tail. At
conception, the head of the sperm enters the egg and unites with the nucleus. The tail falls off,
losing the father’s mitochondrial DNA
Nuclear DNA
Mitochondrial DNA